THE ATLANTIC STURGEON, AC1PENSER OXYRHYNCHUS, IN 



THE DELAWARE RIVER ESTUARY 



Harold M. Brundage III and Robert E. Meadows' 



ABSTRACT 



Records of Atlantic sturgeon, Acipenser oxyrhynchus, captured in the Delaware River estuary from 

 1958 through 1980 were obtained from the literature, unpublished data, and logs maintained by 

 commercial fishermen who took Atlantic sturgeon incidental to their operations for other species. 

 During the period reviewed, there were 130 Atlantic sturgeon reported captured; 64 in 

 commercially fished gill nets and 66 incidental to fishery and ecological studies. Atlantic sturgeon 

 were most abundant in Delaware Bay (river km 0-55) in spring and in the lower tidal river (river km 

 56-127) during summer. This seasonal distribution appeared similar to that described for the 

 Hudson River estuary. Atlantic sturgeon between 800 and 1,300 mm total length were relatively 

 more abundant in the Delaware River estuary than had been reported in other estuaries, suggesting 

 utilization of the Delaware system during a greater portion of the life cycle. 



The Atlantic sturgeon, Acipenser oxyrhynchus, 

 inhabits large estuaries and Atlantic coastal 

 waters from Labrador to eastern Florida; a 

 southern subspecies, A. o. desotoi, occurs 

 throughout the Gulf of Mexico (Vladykov and 

 Greeley 1963). 



The Delaware River estuary, historically one 

 of the major spawning and nursery areas for the 

 Atlantic sturgeon, once supported the largest 

 and most profitable sturgeon fishery on the 

 Atlantic coast (Ryder 1890). The fishery in the 

 Delaware River estuary was extremely short 

 lived, however, and followed a pattern of rapid 

 decline observed in most other estuaries. The 

 commercial fishery, which began in the mid- 

 19th century and expanded rapidly after 1870 as 

 smoked sturgeon and caviar gained acceptance, 

 declined precipitously about 1900 and virtually 

 collapsed by 1905 as the population declined (see 

 Ryder 1890; Cobb 1900; Murawski and Pacheco 

 1977). 



Overfishing of adults on the spawning grounds 

 combined with late maturity appears principal- 

 ly responsible for this decline, although destruc- 

 tion of benthic food organisms by coal silt pollu- 

 tion and general deterioration of water quality 

 and destruction of juvenile Atlantic sturgeon by 

 American shad, Alosa sapidissima, fishermen 

 probably contributed. 



Little is known of the present status of the 

 Atlantic sturgeon in the Delaware River estuary. 



'Ichthyological Associates, Inc., 100 South Cass Street, 

 Middletown, DE 19709. 



Manuscript accepted October 1981. 

 FISHERY BULLETIN: VOL. 80. NO. 2. 1982. 



As a preliminary step towards an assessment all 

 available recent records of Atlantic sturgeon 

 capture in the estuary were compiled. Reliable, 

 quantitative data were found for the period 1958 

 through 1980. Most records were obtained from 

 the substantial body of published and unpub- 

 lished data generated by recent fishery and 

 ecological studies. Further information was ob- 

 tained via personal communication with the 

 staffs of the Delaware River Anadromous 

 Fishery Project of the U.S. Fish and Wildlife 

 Service, the Delaware Division of Fish and 

 Wildlife, and Ichthyological Associates, Inc. In 

 addition, during spring 1979 and 1980, three 

 commercial gill netters who had previously 

 worked with the authors maintained logs of 

 Atlantic sturgeon captured incidental to their 

 operations for other species. Some 25 other 

 fishermen were interviewed to obtain their im- 

 pressions of Atlantic sturgeon occurrence and 

 abundance. Inherent in this approach was the 

 premise that representative trends might 

 become apparent when a body of incidental 

 records and anecdotal accounts are considered 

 together. Apparent trends must be interpreted 

 cautiously, however, since sampling gear and 

 effort varied considerably between and within 

 years. 



To aid in the delineation of spatial-temporal 

 trends the estuary was divided into three regions 

 based on physiography and salinity regime. 

 "Delaware Bay" extends from the mouth (river 

 km 0) to the vicinity of the Leipsic River (river 

 km 55), is shaped like a flattened funnel and has 



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